什么是“湿式减压蒸馏”?
参考答案:
既向加热炉管内注入水蒸气以增加炉管内油品流速;向塔内注入水蒸气,以降低塔内油气分压,达到在低于油品分解的温度下,获得所需要的油品收率。
计算2x2·(-3x3)的结果是( )。
But for friction (摩擦力), people ______ neither walk, nor even stand up.
A.can
B.were able to
C.will be able to
D.could